• Ilpo Järvinen's avatar
    tcp: extend ECN sysctl to allow server-side only ECN · 255cac91
    Ilpo Järvinen authored
    This should be very safe compared with full enabled, so I see
    no reason why it shouldn't be done right away. As ECN can only
    be negotiated if the SYN sending party is also supporting it,
    somebody in the loop probably knows what he/she is doing. If
    SYN does not ask for ECN, the server side SYN-ACK is identical
    to what it is without ECN. Thus it's quite safe.
    
    The chosen value is safe w.r.t to existing configs which
    choose to currently set manually either 0 or 1 but
    silently upgrades those who have not explicitly requested
    ECN off.
    
    Whether to just enable both sides comes up time to time but
    unless that gets done now we can at least make the servers
    aware of ECN already. As there are some known problems to occur
    if ECN is enabled, it's currently questionable whether there's
    any real gain from enabling clients as servers mostly won't
    support it anyway (so we'd hit just the negative sides). After
    enabling the servers and getting that deployed, the client end
    enable really has some potential gain too.
    Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    255cac91
tcp_output.c 73.4 KB